Modification of a spatially referenced crop model to simulate the effect of spatial pattern of subsoil salinity

High levels of subsoil salinity limit the growth and yield of dryland cereals in the Victorian southern Mallee, Australia. Currently available crop simulation models of wheat production perform poorly in this region, presumably due to their inability to account for subsoil limitations, mainly salinity. The objective of this work was to modify a spatially referenced Water and Nitrogen Management Model (WNMM) to account for the spatial pattern of subsoil salinity, by adjusting crop water uptake, in order to explain the spatial variation in wheat yield in this area. Measurements of above-ground biomass and yield of wheat, and the profile of soil salinity (0-80 cm) were made at 40 locations across an 88 ha paddock (35.78°S, 142.98°E) in the Victorian southern Mallee. The S-shaped water stress response function for crop water uptake proposed by van Genuchten (1987) was explored to modify the WNMM by adjusting the water uptake due to salinity, which significantly improved yield simulation over the original WNMM. The improvement in the model's ability to simulate wheat yield indicates that the subsoil salinity limits crop performance in the area. The incorporation of a salinity function in spatial crop models offers potential for simulating yield across a landscape and thus practicing precision agriculture provided salinity impact is considered dynamically.     

Chemical Composition and Bioactivity of Pomace from Selected Fruits

Fruit pomace, a byproduct of the fruit juice industry, is a rich source of nutrients and bioactive components. The study explored chemical composition and bioactive potential of pomace from selected fruits. Results revealed that fruit pomace was rich in dietary fiber (insoluble fiber: 24.15–31.83%; soluble fiber: 0.43–19.71%). Both orange and sweet lemon pomace were good sources of calcium (303 mg/100 g and 581 mg/100 g). Extract yield was high in blue grapes (45.88 mg/100 g). Free radical scavenging activity was highest in blue grape pomace in methanol and aqueous extracts (78.88% and 85.99% per 4-mg extract), respectively. Thus, these pomace could be natural sources of phenolic components.